1. Field of the Invention
The present invention is directed to the field of high voltage commutation distributors for use with internal combustion engines and more specifically to a unique venting system for such distributors.
2. Description of the Prior Art
Electrical commutators, for internal combustion engines, are commonly called distributors and normally include a base attached to the engine, a cap and a shaft. The shaft is gear driven by the engine to rotate in synchronization with the engine. The shaft is normally mounted in the base with a bearing or bushing to provide low frictional rotation about a central axis of the base. A rotor element is attached to the shaft inside a commutation cavity defined by the distributor base and cap. A distributor cap is formed to mount on the base and contains several electrical contacts that are insulated from each other and connected to individual spark plug of the engines. The rotor element may contain one or more commutation electrodes that provide an electrical connection between a common high voltage source electrode and individual ones of the spark plug contacts on the cap.
In prior art distributors, which employ arc-gap conduction between registered electrodes through an air di-electric, ozone is generated as a result of the ionized air produced during arc-over between the registered electrodes. To avoid a high concentration of ozone, which has a lower di-electric constant than air, elimination of the ozone must be achieved.
In U.S. Pat. No. 3,660,626 a sealed type distributor is employed. In order to eliminate the ozone, a decomposing catalyst is employed within the commutation cavity. The catalyst is contained within several catalyst cases, which are sealed units having one end exposed to the commutation cavity inside the distributor. In this case, the catalyst requires periodic replacement and adds additional elements to the cost of the distributor unit.
A more conventional venting system is shown in U.S. Pat. No. 3,646,922, wherein several venting apertures are formed within the distributor cap. The rotating rotor element functions to purge the ozone from the inside of the cavity. An inherent disadvantage in that system, is that the venting apertures, although covered by sintered bronze filters, are closely positioned with respect to the high voltage terminals within the distributor and may provide a potential hazard to service people, or allow moisture and other contaminants to directly enter the commutation cavity.